Capillary hemangioma of the sphenoid sinus excision through the endonasal endoscopic approach

Background: Sinonasal hemangiomas are rare, especially hemangiomas of the sphenoid sinus, for which very few cases have been reported. Observation: We report the case of a 20-year-old patient who had consulted for epistaxis associated with headache. A CT scan of the nose and sinuses revealed a heterogeneous tumor process filling the sphenoid sinus. A minimally invasive endonasal surgery under endoscopic guidance allowed complete removal of the tumor. The histological study of the surgical specimen had revealed capillary hemangioma. After 27 months of decline, no recurrence was noted. Conclusion: Capillary hemangioma is very rare in its sphenoidal location. Endonasal endoscopic excision allows optimal control, after a good pre-operative evaluation.

[Role of dietary fibers in the nutritional management of chronic renal failure]

During the past few decades, considerable attention has been given to the impact of nutrition on kidney disease. Although most dietary attempts to treat chronic renal failure (CRF) and to decrease uremia recommend a protein restriction, another dietetic approach, based on dietary fibers (DF), can lead to the same urea-lowering effect by increasing urea-nitrogen (N) excretion in stool with a concomitant decrease of the total N quantity excreted in urine. In fact, feeding DF results in a greater rate of urea N transfer from blood to large bowel, where it will be hydrolyzed by bacterial ureases before subsequent microflora metabolism and proliferation. Because elevated concentration of serum urea N have been associated with adverse clinical symptoms of CRF, these results suggested a possible usefulness of combining DF with a low protein diet to increase N excretion via the fecal route. These results have been shown in animal models of experimental renal failure and in CRF patients. Further investigations in this population of patients are currently in progress to study whether DF may be beneficial on CRF progression and on CRF terminal stage tolerance. A part of this work is financed by the French Society of Nephrology.

Effects of two fermentable carbohydrates (inulin and resistant starch) and their combination on calcium and magnesium balance in rats

Resistant starch and inulin are complex carbohydrates that are fermented by the microflora and known to increase colonic absorption of minerals in animals. The fermentation of these substrates in the large bowel to short-chain fatty acids is the main reason for this increase in mineral absorption. The purpose of the present study was to examine the potential synergistic effect of a combination of these two fermentable carbohydrates. For this purpose, thirty-two adult male Wistar rats weighing 200 g were used in the present study. The rats were distributed into four groups, and fed for 21 d a fibre-free basal purified diet or diet containing 100 g inulin, or 150 g resistant starch (raw potato starch)/kg diet or a blend of 50 g inulin and 75 g resistant starch/kg diet. After an adaptation period of 14 d, the rats were then transferred to metabolic cages and dietary intake, faeces and urine were monitored for 5 d. The animals were then anaesthetized and caecal Ca and Mg absorption were measured. Finally, the rats were killed and blood, caecum and tissues were sampled. Ca and Mg levels were assessed in diets, faeces, urine, caecum and plasma by atomic absorption spectrometry. Our results confirmed that inulin and resistant starch ingestion led to considerable caecal fermentation in the three experimental groups compared with the control group diet. Moreover, both carbohydrates significantly increased the intestinal absorption and balance of Ca and Mg, without altering the plasma level of these two minerals. Interestingly, the combination of the studied carbohydrates increased significantly the caecal soluble Ca and Mg concentrations, the apparent intestinal absorption and balance of Ca, and non-significantly the plasma Mg level. In conclusion, a combination of different carbohydrates showed synergistic effects on intestinal Ca absorption and balance in rats. Further studies with other types of carbohydrate combinations should be carried out to extend these findings.

[Smoking and atheromatous stenosis of the renal arteries]

Renal vascular pathologies are important causes of the chronic renal failure progression. In these pathologies, the role of smoking in so far as factor of risk was discussed. This work aims to evaluate the effect of smoking exposure on renal arteries of patients with both renal failure and hypertension. 67 patients more than 50 years old, having both renal failure and hypertension, have been explored by arteriography. The active smoking was required among all patients. Patients were classified in 2 groups: group (I) of 45 patients with one or more atheromatous stenoses of renal arteries considered to be significant and group (II) of 22 patients without significant atheromatous stenoses of renal arteries. [table: see text] 80.5% of patients of group (I) have smoked against only 44.4% in group (II). The fact that the presence of atheromatous stenoses of renal arteries was connected to the number of cigarettes and the exposure time, and not to the current comportment of patients towards smoking, this suggested a cumulative effect of smoking.

CONCLUSION

This work shown a relation between the consumption of smoking and the existence of atheromatous stenoses of renal arteries, a reason moreover to fight against smoking. The prevention of smoking intoxication appears important to decrease the incidence of the renal vascular pathologies.

Fermentable carbohydrate and digestive nitrogen excretion

BACKGROUND

Interventions that restrict protein intake lower plasma urea concentration and may slow the progression of renal failure. The question arises whether the effect of a dietary protein restriction could be reinforced by enrichment of the diet with fermentable carbohydrate because these carbohydrates may stimulate the extra-renal route of nitrogen (N) excretion through the digestive route.

METHODS

The influence of fermentable carbohydrate and moderate protein restriction on N metabolism was investigated in a rat model of renal failure with ablation of 70% of renal mass compared with control rats with intact kidneys. Animals were adapted to diets varying with respect to nondigestible fermentable carbohydrate (0% or 10% fructooligosaccharide [FOS]) and with respect to protein content (10% or 18% casein).

RESULTS

Feeding FOS led to a considerable enlargement of the cecum (increase in contents, wall thickness, and blood flow). These changes resulted in a concomitant enhancement of urea N uptake into the cecum and a decrease in plasma urea concentration (-30%). The extent of urea uptake by the cecum was influenced by plasma urea level that was determined by the dietary protein level and by the renal function. Thus, compared with control rats, the rate of urea uptake by the cecum and the total N excreted by the uremic rats was greater under all nutritional conditions. It is noteworthy that, when expressed as a percentage of total N excretion, fecal N excretion nearly doubled in rats adapted to the low-protein diets containing FOS. These effects occurred in both control rats and in uremic rats, in which a 22% decrease in urinary N was recorded as a result of FOS in addition to the low-protein diet. Globally, decreasing the amount of protein in the diet and adding a fermentable carbohydrate led to a decrease in urinary N excretion of more than 65% in uremic rats.

CONCLUSION

These results suggest a possible usefulness for combining fermentable carbohydrate, such as FOS, with a low-protein diet to increase N excretion through the digestive route in detriment of the renal route. This may represent an efficient preventive measure to relieve the renal function in case of renal failure.

Role of fermentable carbohydrate supplements with a low-protein diet in the course of chronic renal failure: experimental bases

During the past few years, considerable attention has been given to the impact of nutrition on kidney disease. The question arises of whether the effect of a moderate dietary protein restriction could be reinforced by enrichment of the diet with fermentable carbohydrates. Feeding fermentable carbohydrates may stimulate the extrarenal route of nitrogen (N) excretion through the fecal route. Such an effect has been reported in several species, including healthy humans and patients with chronic renal failure (CRF). Furthermore, studies of these subjects show that the greater fecal N excretion during the fermentable carbohydrate supplementation period was accompanied by a significant decrease in plasma urea concentration. In animal models of experimental renal failure, the consumption of diets containing fermentable carbohydrates results in a greater rate of urea N transfer from blood to the cecal lumen, where it is hydrolyzed by bacterial urease before subsequent microflora metabolism and proliferation. Therefore, this results in a greater fecal N excretion, coupled with a reduction in urinary N excretion and plasma urea concentration. Because elevated concentrations of serum urea N have been associated with adverse clinical symptoms of CRF, these results suggest a possible usefulness of combining fermentable carbohydrates with a low-protein diet to increase N excretion through the fecal route. Further investigations in this population of patients of whether fermentable carbohydrates in the diet may be beneficial in delaying or treating the symptoms and chronic complications of CRF will certainly emerge in the future. This should be realized without adversely affecting nutritional status and, as far as possible, by optimizing protein intake for the patients without being detrimental to renal function.

Intestinal fermentation lessens the inhibitory effects of phytic acid on mineral utilization in rats

The specific effects of phytic acid (PA) and resistant starch (RS) on mineral bioavailability, namely, Ca, Mg, Fe, Zn and Cu, were investigated in rats adapted to semipurified diets. The diets provided either 73 g/100 g digestible wheat starch (DS) alone, or 53 g/100 g DS plus 20 g/100 g crude potato starch (RS) and either 0 or 1.1 g/100 g PA. A period of 3 wk was first planned to adapt the rats to their respective diets. Compared with rats fed the DS diets, those fed the RS diets had significant cecal hypertrophy and an accumulation of short-chain fatty acids, together with greater cecal blood flow. RS enhanced the cecal absorption of Ca and Mg (from 0.15 to 0.55 micromol/min for Ca, and from 0.10 to 0.35 micromol/min for Mg). Mineral balance was enhanced significantly by RS (Ca, +46%; Mg +50%; Fe +20%; Zn, + 33% and Cu, +61%). PA had no significant effect on Ca or Mg solubility and absorption in the cecum, and it failed to alter significantly Ca or Mg balance. The apparent absorption of Fe, Zn and Cu was significantly lower in rats fed the DS + PA diet than in rats fed the DS diet (Fe, -35%; Zn, -28%; and Cu, -31%). In rats adapted to the RS diet, the inhibitory effects of PA were practically abolished and the mineral balance was restored to the control values. We conclude that the negative effects of PA on mineral balance are relatively minor compared with the stimulatory effect of RS.

Fermentable carbohydrate exerts a urea-lowering effect in normal and nephrectomized rats

The influence of nondigestible carbohydrate on intestinal fermentations and on the route of nitrogen excretion has been investigated in normal rats and in unilaterally nephrectomized rats. Rats were adapted to 10% casein diets, either fiber free or containing different levels of two fermentable carbohydrates, inulin or crude potato starch. Ingestion of fermentable carbohydrate led to a considerable enlargement of the cecum because of hypertrophy of the cecal wall and an increase in cecal contents. Cecal digesta contained elevated concentrations of short-chain fatty acids, resulting in acidic pH. Diets containing fermentable carbohydrate enhanced fecal nitrogen excretion, which was more than doubled at the highest level of inulin or potato starch. In parallel, urinary nitrogen excretion was significantly decreased by fermentable carbohydrate. Although these changes were similar in all animals, there were quantitative differences in the response of nephrectomized animals to fermentable carbohydrate. In nephrectomized rats, plasma urea concentrations were more than 2.5 times higher than in normal rats (5.8 mM compared with 2.2 mM). Plasma urea concentrations were reduced by approximately 50% when normal rats were fed diets containing 7.5-15% inulin or 10-20% resistant starch. In nephrectomized animals fed the highest level of fermentable carbohydrate, plasma urea concentrations were also significantly decreased, but only by 30%. In nephrectomized rats, the concentration of nitrogen cycling in the cecum was greater (urea nitrogen transfer into the cecum was 50-60% greater and ammonia flux from the cecal lumen to the blood was two times higher than in normal rats), but fecal nitrogen excretion was equivalent in normal and nephrectomized animals. When expressed as a percentage of total nitrogen excretion, fecal nitrogen excretion was <20% in animals fed fiber-free diets, compared with 45-50% in normal animals and 40% in nephrectomized animals fed fermentable carbohydrate.

Effectiveness of resistant starch, compared to guar gum, in depressing plasma cholesterol and enhancing fecal steroid excretion

Amylase-resistant starch (RS) represents a substrate that can be administered in substantial amounts in the diet, in contrast to gel-forming polysaccharides, such as guar gum (GG). The aim of this work was thus to compare the effects of GG and RS on cholesterol metabolism in rats adapted to 0.4% cholesterol diets, using dietary GG or RS levels (8 or 20%, respectively) that led to a similar development of fermentations, as assessed by the degree of enlargement of the cecum. The RS diet elicited a marked rise in the cecal pool of short-chain fatty acids, especially acetic and butyric acid, whereas the GG diet favored high-propionic acid fermentations. Both polysaccharides markedly altered the cholesterol excretion, from 50% of ingested cholesterol in controls, up to about 70% in rats adapted to the RS or GG diets. With these diets, the fecal excretion of bile acids was enhanced (67 and 144% with the RS and GG diets, respectively). RS and GG diets were effective in lowering plasma cholesterol (about -40%) and triglycerides (-36%). There was practically no effect of the diets on cholesterol in d > 1.040 lipoproteins (high density lipoproteins), whereas RS (and to a larger extent, GG) were very effective to depress cholesterol in d < 1.040 lipoproteins (especially in triglyceride-rich lipoproteins). Fermentable polysaccharides counteracted the accumulation of cholesterol in the liver, especially cholesterol esters. In parallel, liver acyl CoA:cholesterol acyltransferase was depressed in rats fed the RS or GG diets, whereas only the GG diet counteracted the downregulation of 3-hydroxy-3-methylglutaryl-CoA by cholesterol. These data suggest that RS may be practically as effective as a gel-forming gum, such as GG, on steroid excretion and on cholesterol metabolism.

Acidic fermentation in the caecum increases absorption of calcium and magnesium in the large intestine of the rat

The effect of fermentation on colonic absorption of Ca and Mg was investigated in 8-week-old rats adapted to diets containing either digestible wheat starch (DS diets) or including resistant starch, i.e. 350 g raw potato starch/kg (RS diets). The dietary Ca level of the DS and RS diets was 2.5 or 7.5 g/kg. RS diets resulted in enlargements of the caecum together with hypertrophy of the caecal wall. Acidification of the caecal contents by microbial fermentation of RS was influenced by the dietary Ca level. Very acidic pH conditions and relatively low concentrations of short-chain fatty acids, in the presence of lactic acid fermentation, were observed with the 2.5 g Ca/kg level. Rats fed on RS diets had a higher percentage of soluble Ca (and inorganic phosphate) in the caecum, particularly of rats adapted to the high Ca level. As a result of the hypertrophy of the caecal wall and of an elevated concentration of soluble Ca, the caecal absorption of Ca was 5-6-fold higher in the RS groups than in the DS groups. The difference between dietary intake and faecal excretion (DI-FE) of Ca was higher in rats fed on RS diets than in those fed on DS diets, when the dietary Ca level was 2.5 g/kg. With the higher Ca intake the elevated rate of Ca absorption from the caecum in RS-fed rats was not paralleled by an enhanced DI-EE difference: this suggests a shift of the Ca absorption towards the large intestine. Feeding RS diets also enhanced Mg caecal absorption, resulting in a substantially higher DI-FE difference for Mg, especially with the 2.5 g Ca/kg diets, because a high Ca intake tends to inhibit Mg absorption. The present findings support the view that the large intestine may represent a major site of Ca (and Mg) absorption when acidic fermentations take place. This process could improve the digestive Ca balance when the dietary Ca supply is low; when the Ca supply is affluent, it rather shifts Ca absorption towards a more distal site of the digestive tract.

Resistant starch is more effective than cholestyramine as a lipid-lowering agent in the rat

Amylase-resistant starch (RS) represents a substrate for the bacterial flora of the colon, and the question arises as whether RS shares with soluble fibers common mechanisms for their lipid-lowering effects. It is uncertain whether a cholesterol-lowering effect depends basically on an enhanced rate of steroid excretion or whether colonic fermentations also play a role in this effect. In the present study, the effect of RS (25% raw potato starch), of a steroid sequestrant (0.8% cholestyramine), or both were compared on bile acid excretion and lipid metabolism in rats fed semipurified diets. RS diets led to a marked rise in cecal size and the cecal pool of short-chain fatty acids (SCFA), as well as SCFA absorption; cholestyramine did not noticeably affect cecal fermentation. Whereas cholestyramine was particularly effective at enhancing bile acid excretion, RS was more effective in lowering plasma cholesterol (-32%) and triglycerides (-29%). The activity of 3-hydroxy-3-methylglutaryl-CoA reductase was increased fivefold by cholestyramine and twofold by RS. This induction in rats fed RS diets was concomittant to a depressed fatty acid synthase activity. In rats fed the RS diet, there was a lower concentration of cholesterol in all lipoprotein fractions, especially the (d = 1.040-1.080) fraction high-density lipoprotein (HDL1), while those fed cholestyramine had only a significant reduction of HDL1 cholesterol. In contrast to cholestyramine, RS also depressed the concentration of triglycerides in the triglyceride-rich lipoprotein fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Fermentable fibers or oligosaccharides reduce urinary nitrogen excretion by increasing urea disposal in the rat cecum

The availability of fermentable carbohydrates could influence the digestive degradation and disposal of blood urea. The effects of a poorly fermented cellulosic oat fiber, a soluble fermentable fiber (gum arabic) or one of two oligosaccharides (fructooligosaccharide or xylooligosaccharide) on nitrogen excretion were compared with a wheat starch-based control diet in male Wistar rats. The fibers and oligosaccharides were added to the semipurified diets at 7.5 g/100 g in place of wheat starch. The diets contained 13 g casein/100 g. Oat fiber did not cause an enlargement of the cecum. In contrast, gum arabic and the oligosaccharides elicited a 35-60% enlargement of the cecal wall and a 2 to 2.6-fold mean increase in the cecal pool of short chain fatty acids. Compared with rats fed the oat fiber-based diet, urea flux from blood to cecum was nearly 50% greater and more than 120% greater in those fed the gum arabic and oligosaccharide diets, respectively. In those groups, net nitrogen retention in the cecum more than doubled (nitrogen retention was calculated as the difference between net urea nitrogen flux into the cecum and ammonia nitrogen reabsorption). As a percentage of total excreted nitrogen, fecal nitrogen was 20% in the oat fiber group and 27-29% in the gum arabic and oligosaccharide groups, compared with only 10% in fiber-free controls. Results indicate that under these dietary conditions, the addition of oligosaccharides to the diet induced a 20 to 30% decrease in blood urea and renal and renal nitrogen excretion relative to the control, indicating a potential for oligosaccharide diet therapy in chronic renal disease.

Relationship between fermentations and calcium in the cecum of rats fed digestible or resistant starch

The present studies were undertaken to investigate the effects of the dietary calcium (Ca) level on the Ca balance and on large intestine physiology in rats fed diets providing carbohydrate as digestible wheat starch (DS) or resistant starch (RS). Resistant starch was a high-amylose maize starch. The Ca level ranged from a marginally sufficient level (3 g/kg) to a level in excess of nutritional requirements (6 g/kg). The cecal fermentations were more developed in rats fed RS diets and they were affected by the dietary Ca level, compared to rats fed the DS diets. In rats fed a low Ca RS diet, the cecal fermentations were more acidic than with a high Ca level and there was an accumulation of lactic acid together with depressed concentrations of short-chain fatty acids. There was a considerable accumulation of Ca and phosphate (Pi) in the cecum of rats fed the 6 g/kg level; on the other hand, the concentrations of minerals (Ca, Pi) were very low in the cecum of rats fed the low Ca RS diet. The proportion of soluble Ca in the cecum was markedly enhanced by active fermentations, especially in rats fed the high Ca RS diet (16.3 mmol/l). In rats fed the RS diet, there was a substantial absorption of Ca from the cecum, which was relatively proportional to the dietary Ca level. The above data suggest that in these rats, Ca absorption in the large intestine made a substantial contribution to the digestive balance, probably at the expense of absorption in the upper part of the intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term evaluation of a new selectively biodegradable vascular graft coated with polyethylene oxide-polylactic acid for right ventricular conduit. An experimental study

Low-porosity woven Dacron grafts have been used extensively as an extracardiac conduit in the surgical treatment of congenital and acquired heart diseases involving total heparinization. Caution is still warranted in their use, however, because of long-term complications, including calcification and development of obstructive fibrous peel. In contrast, high-porosity grafts offer much better tissue anchorage and healing but cannot be used under heparinization. We have developed a compound vascular prosthesis in which a knitted Dacron graft is coated with a polymeric biodegradable sealant. Polyethylene oxide-polylactic acid-segmented copolymers comprised the degradable component of the graft. In vitro studies showed that the coated prosthesis exhibited a highly flexible elastomer-like mechanical response. The prostheses were completely watertight, and significant degradation started after 1 week, with absorption completed after 3 weeks. Seven woven and six knitted polyethylene oxide-polylactic acid-coated Dacron grafts used as extracordiac conduits (16 mm), connecting the right ventricle and the pulmonary artery were implanted in dogs. The dogs were killed after 12 to 18 months, and the results are reported. Scanning electron microscopy examination showed peel detachment and nonhomogenous intimal surface with fenestrations in the woven graft group, but complete healing and incorporation of the pseudointima with homogenous, thin lining of the luminal surface in the polyethylene oxide-polylactic acid-coated group. Histologic studies indicated much superior healing and anchorage of the periprosthetic tissue and the pseudointima in the polyethylene oxide-polylactic acid-coated grafts. The biodegradable polymer was fully degraded and exhibited a complete incorporation of the compound vascular prosthesis. This study indicates the superior healing properties of these selectively biodegradable grafts, which might increase long-term patency and decrease complications of right ventricular conduits.

Compositional and structural analysis of PELA biodegradable block copolymers degrading under in vitro conditions

This paper describes an investigation of the in vitro degradation of some polyethylene oxide/polylactic acid block copolymers. It has been found that the faster the degradation, the more basic the incubation medium and, as expected, the higher the temperature. The addition of enzyme proved to have no effect. This study shows that some polyethylene oxide/polylactic acid copolymers exhibit a steady increase in polylactic acid content, as degradation proceeds. This behaviour was attributed to the solubilization effect of the hydrophilic polyethylene oxide chains on the extraction of polyethylene oxide/polylactic acid-degrading fragments. Our findings indicate that polylactic acid blocks are cleaved randomly, the lactoyl end unit playing no special role. In accordance with data published for other biodegradable polymers, the crystallinity of polyethylene oxide/polylactic acid increases as degradation proceeds.

Biodegradable PEO/PLA block copolymers

Poly(ether ester) block copolymers based on polyethylene oxide (PEO) and polylactic acid (PLA) segments were synthesized and characterized, with the aim of developing a new family of bioadsorbable polymers. The materials developed were tailored to meet various mechanical and degradation requirements, and overcome the limitations of the few existing biodegradable polymers. The copolymeric matrices were characterized by means of infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance spectroscopy. The composition of the copolymers synthesized varied between 20 and 84 mol% lactic acid, with PEO chains in the 600-6000 molecular weight range. The solubility properties of the copolymers in a series of organic solvents are described. The equilibrium water content and the water contact angle of various matrices were determined and related to their composition and structure. The incorporation of PEO into the chain yielded highly hydrophilic materials, with equilibrium water contents higher than 60%. Stress/strain curves are presented.

Biodegradable PELA block copolymers: in vitro degradation and tissue reaction

Degradation of, and tissue reaction elicited by a series of polyethylene oxide (PEO)/polylactic acid (PLA) PELA block copolymers were studied in vitro and in vivo. In particular, the effect of pH, temperature and enzymatic activity was addressed. The mass loss was faster, the more basic the media, while, expectedly, PELA copolymers degraded faster with the higher temperature. The addition of an enzyme (carboxylic ester hydrolase) had no effect. The degradation process strongly affected the mechanical properties of the materials under investigation, the elongation at break dropping drastically after two days of degradation. After seven days, only gross observation of the extensively degraded samples was possible. The in vivo studies compared the tissue reaction elicited by various PELA copolymers to that evoked by PLA. Evaluation of tissue reaction observed with a PELA sample after sterilization with gamma radiation showed acute inflammation with considerable dispersion of the material, 12 days after implantation. The granulomatous reaction observed with PELA copolymers after ethylene oxide sterilization was identical to the reaction observed with PLA.

Morphological study of biodegradable PEO/PLA block copolymers

A series of PEO/PLA copolymers, covering a wide range of compositions and segmental lengths, was synthesized, and their morphology was investigated by means of DSC and IR studies. For matrices comprising PEO chains with molecular weights below 3400, no soft-segment crystallinity was detected. When long hard segments were present, essentially monophasic, semicrystalline polymers were obtained, with PLA blocks melting around 130 degrees C. Polymers containing longer soft segments (PEO 6000) exhibited a two-phase matrix, with both components being able to crystallize. The relative degree of crystallinity of PEO and PLA blocks was also determined. The thermal history of the sample strongly affected the morphology of the matrix, especially when both blocks were long enough to crystallize. To further explore these polymers, solvent cast films were prepared and their morphology assessed. Casting from acetone, which is an excellent solvent for PLA, resulted in hard blocks exhibiting lower degrees of crystallinity, while methanol had a similar effect on PEO soft segments.